The present invention relates to testing in fiber optic networks.
Optical fiber connections are generally very susceptible for contamination, dirt, scratches and so on, which can cause faults, such as increased bit error rate, signal degradation, or higher insertion losses. A visual inspection of fiber connectors might therefore be applied. Typically, such visual inspection is carried out using an electronic video microscope consisting of camera unit, monitor, and battery pack. Various devices and methods for surface analysis are disclosed e.g. in U.S. Pat. No. 5,809,162, U.S. Pat. No. 5,179,419, or JP-A-07 218385.
It is an object of the present invention to provide an improved visual inspection for fiber connections. The object is solved by the independent claims. Preferred embodiments are shown by the dependent claims.
According to the present invention, an optical measuring device for measuring in fiber optic networks comprises a measuring unit for carrying out the measurement, a processing unit for processing measuring results, and a display for visualizing processed measuring results. The optical measuring device further comprises an imaging unit for providing imaging signals preferably for allowing a visual inspection of fiber connections. The imaging unit is adapted to connect to the processing unit, which then allows processing the imaging signals so that they can be shown on the display.
In a preferred embodiment, the imaging unit is adapted to be used with different optical objectives, so that it can be used, for example, as microscope or as normal camera unit (e.g. allowing documentation for example of the measurement environment etc.). In one embodiment, the variation of different objective lens systems is achieved by allowing exchanging the objectives. In another embodiment, at least two different objectives are provided (e.g. in one unit), and it can be switched between those objectives.
The optical measuring device preferably is (or is based on) an optical time domain reflectometer (OTDR), a WDM-tester, a dispersion tester, or another fiber optic test equipment. In a preferred embodiment, the measuring device makes use of already existing testing units, whereby the imaging unit can be coupled thereto by means of interfaces (such as USB). The processing unit will be specifically adapted for providing the visualization of the imaging signals to the display. Such adaptation is preferably accomplished by adequate software programs and algorithms, whereby known imaging processing algorithms can be applied.
The invention thus allows utilizing resources for visual inspections, which are already at hand when providing measurements in fiber optic networks. Thus, additional optical inspection devices, such as electronic video microscope sets, are not required anymore and need not be carried around. In particular in field applications, additional and heavy microscopes have been shown as undesired burden for technical staff.
In a preferred embodiment, imaging signals as provided e.g. from an optical fiber connection will be subject to an image processing in order to detect faults. Such faults can be e.g. scratches, particles such as dirt, fluid films (such as oil films), etc. In a preferred embodiment, pattern recognition is provided in order to detect such faults.
In a next step, the imaging signals will be graphically represented, e.g. on a display, screen, or monitor, whereby a visualization of the detected faults is provided by representing such faults in accordance with a predefined coloring scheme. Preferably, different faults will be represented in different colors. In one embodiment, the imaging signals are provided as mono-color signals (preferably black and white signals) or at least with a limited color or gray scale information. The detected faults are then represented preferably in such colors that are not existing in the original imaging signals.
Thus, the invention provides an improved visual inspection of fiber connections, whereby faults will be readily visualized using a fault-coloring scheme. Preferably, a false-coloring scheme is applied, so that detected faults will be represented in non-real, arbitrary colors.
It is clear that the term xe2x80x9ccoloring schemexe2x80x9d is not limited to the application for different optical colors (such as red, yellow, or blue) but also covers mono-color shading e.g. in a black and white representation.
The invention can be partly embodied or supported by one or more suitable software programs, which can be stored on or otherwise provided by any kind of data carrier, and which might be executed in or by any suitable data processing unit. Software is preferably employed for processing the imaging signals.